In semiconductor device manufacturing processes, for example, polishing may be conducted to remove at least part of a simple substance of silicon such as silicon single crystal, amorphous silicon, and polysilicon. Such polishing is normally conducted by using an alkaline polishing composition (refer to, for example, Patent Documents 1 and 2). However, most of known polishing compositions do not allow a simple substance of silicon to be polished at a high removal rate that sufficiently satisfies the requirement of users.
Also, in a case where a simple substance of silicon is polished together with a silicon compound such as silicon nitride and silicon oxide, the use of a neutral or acid polishing composition is desirable. However, known neutral and acid polishing compositions do not allow a simple substance of silicon to be polished at a high removal rate satisfying the requirement of users.
Prior art documents relevant to the present invention include the following Patent Documents 3 to 6 in addition to the above described Patent Documents 1 and 2.    Patent Document 1: Japanese National Phase Laid-Open Patent Publication No. 2002-525383    Patent Document 2: Japanese Laid-Open Patent Publication No. 7-249600    Patent Document 3: Japanese Laid-Open Patent Publication No. 2001-031951    Patent Document 4: Japanese Laid-Open Patent Publication No. 2006-060205    Patent Document 5: Japanese Laid-Open Patent Publication No. 11-302633    Patent Document 6: Japanese Laid-Open Patent Publication No. 2004-266155